DE2625692C3 - Flame-proofing of plastics - Google Patents

Description

for making small amounts of water flame retardant or moisture-containing plastic compositions by incorporation in an amount of 0.2 to 20 Percentage by weight, based on the plastic.

2. Use according to claim 1, wherein component b) is a Ν, Ν'-bis-maleimide group containing polyimide, in particular bis-maleimido-4,4'-diphenylmethane.

3. Use according to one of claims 1 and 2 together with additionally up to 100 percent by weight, based on the phosphorus of a copper, zinc, silver, iron, antimony, vanadium, tin, Titanium and / or magnesium oxide.

Red phosphorus is used in addition to various other purposes, such as the friction surface of matches, also used as a flame retardant for plastics. ' However, this use is limited by the hazards involved, especially pollution and handling under incomplete security conditions. Red phosphorus is an excellent flame retardant making agent, because it is used in much smaller quantities for a given activity can be used as, for example, halogen compounds. In addition, its use in plastics leads to better mechanical properties of these plastics and also does not affect their electrical properties Properties.

From FR-PS 20 52 784 it is already known to use red phosphorus in amounts of 0.5 to 15% as flame-resistant to use making agent in molding compositions based on glass fiber reinforced polyamides. Corresponding DE-OS 17 45 796 z. B. will be 2 to 25 Parts by weight of red phosphorus, optionally passivated with magnesium oxide, in 100 parts by weight of epoxy resin incorporated. The DE-OS 17 20 387 contain up to 25 percent by weight of red phosphorus known flame-retardant synthetic resin compositions based on inter alia. unsaturated polyesters, as well 50 to 400 percent by weight mineral fillers, based on the resin.

However, the red phosphorus used alone and directly in the plastic molding compounds has the Disadvantage that it can be in the form of particles that easily become hot, for example in the presence of Surfaces or under the influence of pressure.

In order to avoid these disadvantages, according to DE-AS 19 65 635 and the corresponding FR-PS 20 74 394 or GB-PS 13 26 929 and DE-PS 20 00 033 the finely divided red phosphorus with a 4 to

Lactam containing 12 carbon atoms, for example caprolactam, is impregnated before being converted into a thermoplastic plastic in a ratio of 1 to 20%. based on the polymer incorporated will. A concentrate of the thermoplastic material and 20 to 75% by weight can also be used initially Lactam-treated red phosphorus is made and then diluted with additional amounts of the plastic will. The disadvantage is that the lactams are hygroscopic and the water present in the mixture causes the formation of highly toxic hydrogen phosphide, which ignites spontaneously in the air, especially at the processing temperatures of the plastics. Therefore, the lactam must during or after the incorporation of the phosphorus-lactam mixture into the Plastic can be completely or partially removed again by distillation.

The known from DE-OS 23 08 104, made flame-retardant with red phosphorus contain plastics In addition, a substance that binds hydrogen phosphide, preferably copper (II) oxide and activated carbon, to the To prevent the release of hydrogen phosphide during storage at room temperature. the However, the addition of these substances is not sufficient to prevent the release of hydrogen phosphide at high temperatures to prevent.

In order to make textiles flame-resistant, according to GB-PS 13 46 246 the red phosphorus is together with synthetic resins e.g. B. unsaturated polyesters applied as a binder on the textiles and then the Cured binder.

Attempts have also been made to combine red phosphorus with inert liquid organic or organosilicon compounds (DE-OS 22 49 638) or with aminoacetic acid derivatives (US-PS 38 06 488). Characteristic for the former is their low vapor pressure, which is why they are used when processing the Plastics can sweat out or evaporate because of the higher temperatures and often used for shaping Pressures must be applied. These compounds include common PVC plasticizers such as Dioctyl phthalate and phosphoric acid ester. The red phosphorus stabilized in this way is certainly suitable for PVC, but not without further ado for any other plastics. The aminoacetic acid compounds in turn are actually not a stabilizer for the red phosphorus, but are used in the commercially available To neutralize or intercept the accompanying substances iron and copper contained in phosphorus. For polyamides is this addition useful; however, it can impair the properties of other plastics. In In those cases in which the phosphorus companions iron and copper do not interfere, the acetic acid derivatives are complete not interesting. In addition, they prove themselves under most of the processing conditions for plastics also as unstable.

The task is thus to enable the use of red phosphorus in plastic without that mainly due to the processing temperatures of the plastic and the presence of low Amounts of water or moisture in the plastic to be processed, phosphorus hydrogen is released can be and the means used here under the processing conditions for Kunsi materials proves to be permanent.

It has now been shown that this object can be achieved with the aid of the use specified in the claims can be solved.

As red phosphorus in the sense of the description, all colored allotropic forms, namely red, violet or black phosphorus, which are traded as red phosphorus and contain up to 3% by weight May contain metal oxides or metal salts as stabilizers.

This red phosphorus must be in the form of a grain with an average particle diameter <200 μm, preferably <100 μm, are present. One uses a very fine grain with a diameter of only a few μπι, it can be used to spun textile products Equip flame retardant.

The compounds that still contain maleic, fumaric acid or allyl type unsaturation are for the purposes of the description essentially the polymers or prepolymers of the unsaturated type Polyesters or polyimides or copolymers based on maleic anhydride or maleic acid ester or fumaric anhydride or ester.

The unsaturated polyester, the still unsaturated bonds based on maleic acid, fumaric acid or contain crotonic acid are well known. They are specifically described in Encyclopedia of Polymer Science and Technology ", Vol. 11, p. 129 ff. (Intersciences Publishers). These polyesters include the polydiol fumarates dissolved in styrene, allyl phthalate or Methyl methacrylate and polymers based on allyl phthalate.

The copolymers based on maleic anhydride or maleic acid ester or fumaric anhydride or - esters are just as well known. They are described in the abovementioned publication, Vol. 2, pp. 80 ff.

The polyimide-like prepolymers are uncrosslinked or incompletely crosslinked dissolution products a Ν, Ν'-bisimide of an unsaturated dicarboxylic acid of the general formula I.

CO

CO

Ν — Α — Ν

CO

CO

in which D is a divalent organic group containing a carbon-carbon double bond, and A is a divalent organic group having 2 to 30 carbon atoms.

The prepolymers and polymers obtained by reacting a compound of the formula I with a Polyamine are obtained are described in FR-PS 15 55 564 (GB-PS 11 90 718). In formula I leads D is derived from the anhydride of an ethylenic dicarboxylic acid of the general formula

CO

CO

away; preferably this is maleic anhydride or dichloromaleic anhydride. According to the FR-PS 14 55 514 (US-PS 33 80 964) produced poly (bis-maleimides) are also suitable.

If these polymers are liquid, they can be applied to the surface of the in any known manner individual phosphor particles are applied. If they are solids, they become intimate in the form of a powder mixed with the phosphor powder and homogenized. It is also known that the addition of

Metal oxides or metal salts stabilize the red phosphorus; the commercially available red phosphorus generally includes such stabilizers. The addition of metal oxides, thereby possibly occurring Elimination of phosphorus hydrogen is reduced, is within the scope of the invention. The best Results are obtained with the oxides of copper, zinc, silver, iron, antimony, vanadium, tin, or titanium Magnesium, especially achieved with copper oxide

How much metal oxide is added depends on the amount of resin used and the processing conditions of the plastic as well as the nature of these plastics. Usually up to 100% by weight, based on the red phosphorus, of metal oxide can be added.

For the production of moldings, which are increasingly non-flammable or flame-resistant should be, a lot of plastics come into question. Numerous molding compounds can be used in accordance with the invention Flameproof on the basis of thermoplastic, thermosetting or elastomeric polymers. Thermoplastics include:

Polyolefins, such as high or low density polyethylene, polypropylene, polyfluoroethylene and copolymers of ethylene and propylene,
Polyvinyl resins, such as polyvinyl chloride and copolymers based on vinyl chloride,

Polystyrenes and ABS copolymers (acrylonitrile butadiene styrene),

Polyamides, such as polyhexamethylene adipamide, polycaprolactam, Polyhexamethylene sebacamide, polyundecanamide, polylauryl lactam, polyhexamethylene azelamide,

saturated polyesters such as polyethylene glycol terephthalate or polybutylene glycol terephthalate,
Polycarbonates, polyacetals and polyacrylic resins such as polymethyl methacrylate,

Cellulose esters, polyurethanes or polyamide-imides. Thermosetting plastics include Phenolic resins, aminoplasts, unsaturated polyesters, polyepoxides and the polyimides.

Various elastomers can also be made flame-resistant according to the invention. For this include natural or synthetic rubbers, silicones, and polyurethane elastomers.

All of these plastics, especially when they are used for the production of moldings, usually with processed various additives: reinforcing fillers such as glass fibers, fillers that make up the moldings to confer certain properties or which are inert such as kaolin or talc, antioxidants, various Stabilizers, dyes or pigments. Usually, with an addition of 0.2 to 20% by weight flame retardant, based on the plastic, a good effect is achieved.

example 1

40 g of prepolymer obtained by the action of 2.5 mol of 4,4'-bis-maleic acid imidodiphenylmethane on 1 mol of 4,4'-diaminodiphenylmethane, softening point 100 ° C., were dissolved in 100 cm ^{3 of} dimethylformamide. While stirring, 60 g of phosphor powder (red) with a grain size of 20 to 30 μm were added. The whole was stirred for 10 minutes and then left to rest for 12 hours.

Then the Phosohorsusnension became a

60

Mixture of 1 l of methanol and 2 l of water poured in with vigorous stirring with a turbine. It was then filtered, ^{washed with 200 cm 3 of} methanol and washed twice with 200 cm ^{3 of} ether. The precipitate was dried; 88 g of red phosphorus were obtained in powder form on which the resin had precipitated.

In a jacketed and heated 1-1 autoclave with a propeller stirrer (20 rpm), 25.6 g of coated red phosphorus and 300 g of polyhexamethylene adipamide with an average molecular weight of 20,000 and an inherent viscosity in m-Kxesol of 13. The whole was heated to 285 ° C. in the course of 1 hour, with stirring, and this temperature was maintained for 1 hour.

To determine the possibly released hydrogen phosphide, the gases emerging from the autoclave were ^{collected in two 1000 cm 3} flasks connected in series, which contained 750 cm ^{3 of} an aqueous, 2% solution of mercury chloride; the acid formed was titrated in the presence of methyl orange. This method of determination is described by Wilmet in "Comptes rendus de l'Academie des Sciences" 185, p. 206 (1927).

1.4 mg of released hydrogen phosphide, based on 1 g of red phosphorus used, were determined.

A comparative experiment was carried out with 18 g of red phosphorus (not coated); were here 33.5 mg of hydrogen phosphide are released per g of red phosphorus used.

The flame-proofing effect according to the invention was determined as follows:

Test specimens 100 × 6 × ³ mm 3 were produced by cold pressing under a pressure of 300 kg / cm ² , and the oxygen limit value or the oxygen limit number was determined in accordance with the LOI test of the ASTM D 2863 standard. The following results were obtained:

Polyamide alone

Polyamide + red phosphorus

Test LOI

20.8

27-28

40 examples 3 and 4

The procedure was as in Examples 1 and 2, but 6 g of copper oxide for each experiment in the autoclave admitted. In the following test, no formation of hydrogen phosphide was found.

Example 5

11.1g of powdered 4,4'-bis-maleic acid imidodiphenyl methane and 18 g of phosphor powder (red) were mixed together and the whole as in Example 1 incorporated into the plastic in the autoclave under the same conditions. It was only 3.9 mg Hydrogen phosphide detected per g of red phosphorus used.

Example 6

A single screw press for laboratory was used, length of screw 415 mm, diameter 15 mm. The diameter of the cylindrical nozzle head was 3 mm. The temperatures were at the material inlet 250 ⁰ C, in the middle of the extruder 280 ° C and in the nozzle head 270 ° C.

A simple mixture of the following composition was prepared:

100 g of poryhexamethylene adipamide with an average molecular weight of 20,000 and an inherent viscosity in m-cresol of 1.3,

9.8 g coated or coated phosphor according to Example 2,
2 g copper oxide (powder).

This mass was introduced into the extruder and extruded as a rod.

During the entire process, tests were carried out at various locations on the extrusion press to determine whether this was the case Phosphorus was released with the help of the DRAEGER CH 31 101 pipe. Another test was carried out after the rod exited the extruder, after the still warm, extruded Body had been broken. All tests were negative.

Example 2

40 g of 4,4'-bis-maleic acid imidodiphenyl methane were dissolved in 150 cm ^{3 of} dimethylformamide. While stirring, 60 g of phosphor powder (red) with a grain size of 20 to 30 μm were mixed in. The whole was stirred for a further 5 minutes until a homogeneous suspension was obtained. This suspension was poured into a mixture of 1 l of methanol and 2 l of water with very vigorous stirring (turbine).

The precipitate was filtered off, ^{washed with 200 cm 3 of} methanol and then twice with 200 cm ^{3 of} ether and dried. 97 g of red phosphorus (powder) were obtained on which 4,4'-bis-maleic acid imidodiphenylmethane had deposited.

The procedure was then as in Example 1 with 29.1 g of the above coated phosphor. The 4,4'-bis-maleic acid imidodiphenyl methane was crosslinked to a polyimide at the processing temperature. There was very little evolution of phosphine solid, namely only 0.9 mg / g red phosphorus used.

The LOI test was carried out as in Example 1. An oxygen value of 27.5 to 28 was obtained.

Example 7

88 g of granulated polytetramethylene glycol terephthalate were placed in a rotating cylinder with stirring (Viscosity 3500 P), 0.3 g of polyethylene glycol laurate, 2 g of copper oxide (powder) and 9.8 g of coated red Phosphorus according to Example 2 mixed. This molding compound was in the extrusion press according to Example 6 introduced and extruded into rods. The temperature at the material inlet was 215 ° C, in the middle of the Extrusion press 240 ° C and in the die head 235 ° C. At no point was there any released hydrogen phosphide proven. Then the LOI test was carried out. An oxygen value of 23 to 23.5 was obtained (Polyester alone 21).

60

Example 8

The procedure was as in Example 7, but the polyester was replaced by the same amount of polypropylene powder W = 0.9O3; Melting range 165 to 170 ⁰ C; Flow number 6) replaced. The temperatures of the extruder were at the material inlet at 205 ° C, in the middle of the extruder at 22O ⁰ C and in the nozzle head at 205 ⁰ C. It was the test LOI performed and an oxygen value of 19 to 19.5 was obtained (polypropylene alone 17) .

7 8

_B. "240 ° C in the middle of the extruder and 230 ⁰ C at the

Nozzle head. The LOI test was carried out and a

The procedure was as in Example 7 and the oxygen value from 22 to 23 (polystyrene alone 20)

Polyester obtained by the same amount of polystyrene powder.

(VICAT temperature 96 ° C; d = 1.05; flow number 4 to 4.5 ■ -> Extrusions were used in all of these experiments

at 200 ° C / 5kg). The temperatures in good quality without any trace of phosphorus

Extrusion press were 220 ° C at material inlet, hydrogen received.

Claims (1)

Patent claims: 1. Use of an agent in the form of a mixture a) 50 to 95 percent by weight red phosphorus with an average grain size <200 μπι and b) 5 to 50 percent by weight of one or more polymers or prepolymers that are still have unsaturated maleic, fumaric or allyl-like bonds,